1. Field of the Invention
The present invention relates to a communication apparatus which is capable of performing voice communication and image communication in parallel, with an external apparatus via a network, and a communication method therefor, as well as a program for implementing the communication method and a storage medium storing the program.
2. Description of the Related Art
In recent years, attention has been being given to communication apparatuses of a type capable of performing voice communication by IP telephone and image communication by IP fax communication according to ITU-T Recommendation T.38, using Session Initiation Protocol (hereinafter referred to as SIP (see IETF RFC3261)) for managing communication sessions.
One of reasons why such communication apparatuses have attracted attention is that voice/image communication using SIP+T.38 makes it possible to perform voice transmission and image transmission, in parallel, to the same receiving end or destination, differently from conventional communication through a public telephone line.
For example, Japanese Laid-Open Patent Publication (Kokai) No. 2005-33523 proposes a method in which scanned image data is sent to an IP telephone communication partner simply by pressing a start key of a communication apparatus during voice communication by IP telephone in a state where a fax original is set on the apparatus. The use of the technique disclosed in Japanese Laid-Open Patent Publication (Kokai) No. 2005-33523 makes it possible to save time and labor required to designate a destination for IP fax transmission.
Another reason is that message transmission can be performed using a message request. The message request is defined in the IETF RFC3428 Session Initiation Protocol (SIP) Extension for Instant Messaging, and is applicable to communication using SIP.
For example, Japanese Laid-Open Patent Publication (Kokai) No. 2006-74308 proposes a technique of notifying a communication partner of the status of IP fax communication using a message request. When the technique disclosed in Japanese Laid-Open Patent Publication (Kokai) No. 2006-74308 is used, if an apparatus at the receiving end desires to display an error message on a terminal apparatus at the transmitting end, it is possible to send the error message using a message request, to thereby cause the transmitting-end terminal apparatus to display the received error message on a screen thereof.
However, in the above-mentioned conventional technique, it is not envisaged to notify a user of the status of image transmission through IP fax communication or the like in a case where voice communication and image communication are performed in parallel. For this reason, the user cannot easily know the status of image transmission to a communication partner. More specifically, even when the user is using a cordless handset wirelessly connected to an IP telephone set provided e.g. in a multifunction peripheral, it is required to stay by the machine so as to check the status of image transmission/reception, which is disadvantageous in user-friendliness.